Staging to define risk category will be conducted only for those non-diabetic relatives who screen positive for ICA and consent to undergo further evaluation. It is possible to identify impending clinical Type I DM throught the detection of autoantibodies directed against self-antigens of the pancreatic B cells. since first degree relatives of probands with Type I have more than a ten-fold risk of Type I DM than in the general population, the DPR study will focus on such relatives. the staging will include measurement of insulin autoantibodies (IAA) ( and possible other islet realted immune markers) and intravenous glucose tolerance testing (IVGTT) to assess first phase insulin response (FPIR), using the sum of the plasma insulin values of the 1 and 3 minute samples, noted as Insulin sum(1'+ 3'). Samples will also be obtained for molecular HLA-DQ typing. For relatives meeting initial eligibility criteria, oral glucose tolerance testing (OGTT) will be performed to characterize state of carbohydrate tolerance, both to exclude diabetes and enable the stratification of relatives with impaired or indeterminate glucose tolerance.